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Addind a Steam Catapult

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Re: Addind a Steam Catapult

Postby StuartC » Sun Feb 12, 2017 3:59 pm

Interesting thing I just noticed.

If I edit in the above cat code into the AC file, then load the AC in blender, I can see the "Cat" and move it into position. All good..........
But, if I load the model avain, the wire is missing and all I'm left with is a point at the start and another and the end of where the cat should start and finish.
Looking at thwe AC file in a text editor shows "loc -28.3239 0 -25.271" is now missing completely, "Numvert" now =3 and the section
" refs 2
0 0 1
1 1 0" is missing completely.
I think its blender screwing me over here. If I try to add the missing lines back in, the 3d model will fail to load in blender or ac3d.
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Re: Addind a Steam Catapult

Postby Richard » Sun Feb 12, 2017 4:30 pm

in that case it'll be because blender doesn't think it's a valid tri, quad or polygon.

Try changing the Nimitz to have the catapult interaction on Deck-1 rather than cat-1 - looking at the code it might work with this. If that doesn't work make a quad (or tri) in blender and see if that works.
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Re: Addind a Steam Catapult

Postby StuartC » Sun Feb 12, 2017 4:44 pm

Editing the thing manually and getting it into position has resulted in a positive launchbar lock and cat launch.
Now, a new problem has arisen. The cat is too short to reach launch velocity..................
Similarly, the arrestor wires are too slack for the short deck on the carrier.

any ideas ?
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Re: Addind a Steam Catapult

Postby stuart » Sun Feb 12, 2017 8:51 pm

Hi StuartC,

I've had a look at the YASim code (on the assumption you've got a YASim aircraft).

It looks like by default, it applies an acceleration of 25m/s^2 (i.e. ~2.5G). However you can set this by using an an LACCEL input channel on the launchbar object. Confusingly a value of 0.25 maps to 2.5G.

A quick grep shows that the Buccaneer uses this property, and sets it expliitly as follows:

Code: Select all
<launchbar    x="-7.77252"
                     y="0.0"
                     z="-0.370128"
                     length="3.5052"
                     down-angle="90"
                     up-angle="0"
                     holdback-x="-16.3"
                     holdback-y="0.0"
                     holdback-z="0.1175"
                     holdback-length="2.0">
      <control-input axis="/controls/gear/launchbar"
                            control="LEXTEND"/>
      <control-speed control="LEXTEND"
                            transition-time="1"/>
      <control-input axis="/controls/gear/launchbar/acceleration-norm"
                            control="LACCEL"/>
   </launchbar>


... and in the -set file sets /controls/gear/launchbar/acceleration-norm to 0.75, implying 7.5G of acceleration (yikes!). I guess that might be right.

So I think you can just copy-and-paste the control-input tag, and then experiment until you get a suitable launch velocity.

From a code read of the Arrestor wires, I _think_ it applies constant deceleration, and can't be modified :(. However, there is someone working on YASim right now (see the -devel list), and if you email them, they might be prepared to add a control input element to the hook as there is for the launchbar.

Hope that helps.

-Stuart
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Re: Addind a Steam Catapult

Postby StuartC » Sun Feb 12, 2017 11:06 pm

Ok, so this requires each aircraft to be modified, not the actual cat's. Nothings ever simple.
I'll have a play with it tomorrow I think.
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Re: Addind a Steam Catapult

Postby StuartC » Mon Feb 13, 2017 2:28 pm

Tried the Buccaneer, and cant get it to engage at all, so I modified one of the Yasim Phantoms ( as they served on R09 ).

Yhe launchbar in the yasin looks like:-

<launchbar x="6.8"
y="0.0"
z="-1.0"
length="3.5052">
<control-input axis="/controls/gear/launchbar"
control="LEXTEND"/>
<control-speed control="LEXTEND"
transition-time="1"/>
<control-input axis="/controls/gear/launchbar/acceleration-norm"
control="LACCEL"/>
</launchbar>

It Engages with the Cat and I get the Engaged message on screen.

added this to the gear section in the set file:-
<launchbar>
<acceleration-norm type="float">0.95</acceleration-norm>
</launchbar>

When I go for a cat launch, at full power I reaching the breathtaking speed of 38kts, then I get wet and to top it off, get run over by the ship.
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Re: Addind a Steam Catapult

Postby StuartC » Mon Feb 13, 2017 4:15 pm

Tested with the acceleration-norm value set up to 500.0 without any noticeable change in departure velocity, but If I use the same values and launch from the Nimitz, its warp speed.

Somethings missing.
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Re: Addind a Steam Catapult

Postby wlbragg » Mon Feb 13, 2017 4:34 pm

The launchbar in the yasin looks like:-

Code: Select all
/controls/gear/launchbar/acceleration-norm"


added this to the gear section in the set file:-

Code: Select all
<launchbar>
<acceleration-norm type="float">0.95</acceleration-norm>
</launchbar>


So former equals
/controls/gear/launchbar/acceleration-norm

The latter equals (without me seeing the code)
/gear/launchbar/acceleration-norm

Just a guess!
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Re: Addind a Steam Catapult

Postby StuartC » Mon Feb 13, 2017 4:46 pm

If it was wrong, it wouldn't have made any effect on the test launch from Nimitz, but it did. There is something in the Nimitz that's missing from this carrier, and I cant find what.
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Re: Addind a Steam Catapult

Postby StuartC » Mon Feb 13, 2017 8:50 pm

Further testing.
placing an unmodified ( length ) of cat from the Nimits onto the carrier gives a successful launch.
The French carrier has shorter cats, so a test launch from that ship also works, as does transplanting a raw cat from it onto the deck of the carrier.
Now, if I shorten ether cat even slightly, they loose all the launch power and I end up trundeling off the deck again at 40 kts.
Theres something somewhere which is defining the length of the cats on the different ships. and when you change the length, they brake.
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Re: Addind a Steam Catapult

Postby Necolatis » Tue Mar 14, 2017 11:10 pm

StuartC wrote in Sun Feb 12, 2017 3:59 pm:Looking at thwe AC file in a text editor shows "loc -28.3239 0 -25.271" is now missing completely, "Numvert" now =3 and the section
" refs 2
0 0 1
1 1 0" is missing completely.
I think its blender screwing me over here. If I try to add the missing lines back in, the 3d model will fail to load in blender or ac3d.


If the model don't load properly into Blender, do you mind letting me having a look at the model?

Btw. SURF 0x02 means its a single-sided open line. (meaning, its not looping back on itself)
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